Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

627
FXUS63 KLOT 072301
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
501 PM CST Sat Mar 7 2026

.KEY MESSAGES...

- Unseasonably warm and breezy conditions are expected Sunday
  and especially Monday.

- Rain and some thunderstorms are likely late Tuesday into
  Wednesday, with a corridor of heavy rain possible somewhere in
  or near the area.

&&

.DISCUSSION...
Issued at 156 PM CST Sat Mar 7 2026

Temperatures have steadied in the 40s this afternoon after a
cold front cleared the area over the past few hours. Pre and
post-frontal drizzle has also diminished, with dry conditions
expected late this afternoon through tonight. An expansive area
of upstream stratus should edge eastward through this evening
before gradual low-level backing and drying begin to
scatter/erode the stratus overnight. Unseasonably warm
conditions will return Sunday and especially Monday amid breezy
southwest winds and mostly clear skies.

Ensemble spread continues to narrow midweek as a northern
stream tough over the northern Rockies phases with an upper-
level low drifting northeast from the Baja of California. Ahead
of the phasing waves, a persistent flow of Gulf moisture will
push PWATs into unseasonably high values. Meanwhile, a slow-
moving cold front originating from a wave passing just north of
Lake Superior on Monday will likely stall over or near the
forecast area on Tuesday. Overall, this will set the stage for a
very wet period late Tuesday through Wednesday, with a
conditional severe weather setup south of the boundary on
Tuesday. With a constant feed of moisture overrunning the
stalled boundary, notable deformation under the entrance of a
strong upper-level jet stream, and modest lapse rates aloft,
this pattern is becoming increasingly favorable for an axis of
heavy rain. Recent ensemble guidance is a bit concerning with
mean QPF values nearing 1.5-2" during this period. In fact, a
vast majority of ensemble members and deterministic guidance
place a 2-3" swath of rain somewhere in or near the CWA. Will
continue to monitor trends in guidance with respect to changes
in phasing of the aforementioned waves, but increased flooding
messaging may be needed within the next few days, particularly
if heavy rain is expected to settle over areas that received
appreciable rain over the past couple days.

On the heels of the midweek system, another system is progged
to pass just north of the area Thursday night into Friday.
Temperatures may be on a bit of a roller coaster, with an
unseasonably warm day Friday sandwiched between seasonable
temperatures Thursday and Saturday.

Kluber

&&

.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 501 PM CST Sat Mar 7 2026

Expansive low-end MVFR stratus is present across the airspace
this evening with cloud bases lowering toward IFR with westward
extent. The expectation remains that the back edge of stratus
will continue working eastward this evening, though exactly when
each individual terminal will scatter out remains an item of
low confidence. Will maintain the inherited timing of 03-05Z or
so for scattering and make adjustments if needed with the
upcoming scheduled 03Z AMD. Outside of stratus, gusty west winds
this evening should slowly subside as a surface pressure ridge
shifts eastward into the Great Lakes. The tightening of the low-
level pressure gradient on the backside of the surface pressure
ridge will support the development of a low-level jet, leading
to LLWS criteria being met at all but GYY from roughly 09-14Z
tomorrow morning.

The surface pressure ridge will shift eastward after daybreak placing
the airspace in a southwest flow regime. An ensemble of
forecast soundings supports southwesterly gusts increasing to
the 20-25kt range by mid-morning, though a gust to 30kt cannot
be ruled out as mixing builds into the decaying low-level jet
just after daybreak. Breezy southwest winds will then prevail
through the remainder of the TAF period. FEW to SCT mid- to
upper-level cloud decks will stream overhead from time to time
tomorrow afternoon.

Borchardt

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 6 PM CST this evening for the IL
     and IN nearshore waters.

&&

$$

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